 str1="hello"
 str2="world"
 str3=('"hello'
       'world"')
 print(str1)
 print(str2)
 print(str3)
 print('hel\'loworld')
 print('123---{0}---{1}---{2}'.format('4'))
 print(f'123---{str1}')

for i in range(0,101,2):
    print("----------开始下载----------")
    if i==100:
        print("下载完成")
    else:
        str4="*"*(i//2)+"."*((100-i)//2)
        print(f'{i}%{str4}')